Combustion Air Contaminants

What are Combustion Air Contaminants?
Combustion air contaminants are Combustion air contaminants are pollutants that are a byproduct of the fuel burning process. Some combustion air contaminants such as nitrogen dioxide or sulfur dioxide can be seen or smelled in the indoor environment. Others such as carbon dioxide, carbon monoxide, and nitric oxide and ultrafine particles are colorless, odorless, and tasteless.

Sources of Combustion Air Contaminants
Combustion air contaminants come from  a wide range of sources in the home. Fuel burning appliance, including furnaces, water heaters, ranges, coal or wood stoves, fire places etc. are candidates for producing indoor air pollution. The amount of indoor air ventilation, as well as the condition of appliances and chimneys or vents, are contributing factors.  Combustion gases may also enter the home by back drafting or from a blocked chimney. Black stains on the outside of a chimney could indicate pollutants entering your house. A yellow natural gas flame may indicate incomplete combustion which would release of pollutants inside the home.


Health Effects of Combustion Air Contaminants

    • Nitrogen Dioxide: Causes respiratory irritation, increased airway resistance. Chronic exposure can decrease lung function while increasing the risk of respiratory  infection, including pnumonia.
    • Sulfur Dioxide: Causes irritation and constriction of the throat in asthmatics who exercise, as well as increasing risks for lung infection .
    • Ultrafine Particulates: Chemical makeup and/or volume may cause a wide range of adverse health effects. Can only be detected by special equipment and testing.
    • Carbon Dioxide: Colorless, odorless and tasteless, it is an asphyxiant responsible for headaches, nausea and dizziness. At high concentrations it can lead to coma or even death.
    • Carbon Monoxide: Also undetectable to the human senses, exposure to low concentration lead to symptoms that are often mistaken for a cold or flu and can cause headaches, irratability, and fatigue. Carbon monoxide may also accumulate over time. At high concentrations it can lead to coma or even death.
    • Nitric Oxide: Another contaminant undetectable by sight smell or taste, this has comparable health effects to carbon monoxide at lower exposure levels.

    Do I Have Combustion Air Contaminants?
    Some combustion air  contaminants are easily identifiable by sight or smell.  Smoke or gases may be visibly leaking from appliances, vents or chimneys,  or will give off a pungent or smoky aroma when present.  Other combustion air contaminants are impossible to detect by sight, smell or taste.  Homeowners can purchase testing devices to detect these chemicals, but must also be aware that home tests are not always sensitive enough to detect a problem. If you experience persistent symptoms such as headaches, sleepiness dizziness, watery eyes or breathing difficulties while inside your home, combustion air contaminants may be the cause.
    What if I Have Combustion Air Contaminants in My Home?
    Proper installation and  maintenance of combustion appliances and their vent or chimney assemblies are critical to reducing indoor air pollution. Proper ventilation of  your home and the enclosed spaces, as well as a carbon monoxide detector, are also essential. Houses in Alaska during the winter heating season are prone to buildup of contaminants If symptoms persist after these steps have been taken, consult a professional IAQ specialist